1. Field of the Invention
The present invention relates generally to image processing, and more particularly, to a method and apparatus for interpolating image data corresponding to a CFA (color filter array) such as a Bayer CFA.
2. Description of the Related Art
Image-sensing systems such as digital still cameras, mobile phone cameras, or the like include an image-sensing device in an active pixel sensor array form. Such an image-sensing device generates digital image data with three colors (i.e., green (G), blue (B), and red (R)) in a Bayer color pattern as shown in FIG. 1. In a case where an image-sensing device adopts a Bayer color filter array (CFA), a Complementary Metal-Oxide Semiconductor (CMOS) image sensor (CIS) for each pixel generates image data corresponding to one of the R, G, and B colors.
If an image were displayed using only each pixel data generated by the image-sensing device, the displayed image would be seriously distorted with poor visual quality. Therefore, a subsequent interpolator determines two missing color components for each pixel data using neighboring pixel data. An image displayed using the resulting three-color data for each pixel has improved visual quality.
Well-known interpolation methods include a bilinear interpolation method, a smooth hue-transition method, a PEI's method, a directional interpolation method, an Adams' method, an Adams-PEI method, a Kimmel's method, and so on. U.S. Pat. No. 5,506,619 and Korean Patent Application No. 2001-56442 disclose conventional interpolation methods of obtaining pixel data of two missing colors for each pixel using neighboring pixel data.
However, in the above-mentioned conventional interpolation methods, distortion of a displayed image is not fully corrected. Distortion of an image includes a zipper effect, i.e., aliasing, color moire, loss of detail blurring, a false/pseudo color effect, and the like.